Potassium Hydroxide In Dimethyl Sulfoxide Research Articles

Preparation and properties of micro- and nanocomposites composed of a water-soluble nylon and aramid fibers

A commercial 20 wt% solid paste of microfibrillated aramid fibers (MFAs) containing water was treated with potassium hydroxide in dimethyl sulfoxide to produce aramid nanofibers (ANFs). Nanocomposites composed of a water-soluble nylon (A-90, amine-modified poly(ɛ-caprolactam)) and ANFs with fiber contents of 0–5 phr (i.e., parts per hundred resin) were prepared by a casting method of the resin/fiber dispersion in water. A-90/MFA microcomposites were also prepared by the same method for comparison. The FE-SEM analysis revealed that ANFs are much finer than MFAs, and both the fibers are homogeneously dispersed in all the composites. The glass transition and maximum thermal decomposition temperatures of A-90/ANF and A-90/MFA composites were higher than those of A-90. The tensile strength, tensile modulus and elongation at break for A-90/ANF and A-90/MFA composites increased with increasing fiber content. When tensile properties of A-90/ANF and A-90/MFA composites with the same fiber content were compared, A-90/ANF nanocomposites exhibited much better tensile properties than A-90/MFA composites did. Especially, the tensile toughness of A-90/ANF 5 phr was about three times higher than that of A-90.

ChemInform Abstract: Base‐Mediated Addition of 1‐(2‐Hydroxyalkyl)pyrroles to Acetylene: Atom‐Economic Route to 1‐[2‐(Vinyloxy)alkyl]pyrroles.

Nucleophilic addition of 1-(2-hydroxyalkyl)pyrroles to acetylene, an unactivated carbon–carbon triple bond, in the presence of a base has been studied. As a result an atom-economic synthetic method to obtain 1-[2-(vinyloxy)alkyl]pyrroles in good yields employing superbase, sodium or potassium hydroxide in dimethyl sulfoxide, systems has been developed. 1-[2-(Vinyloxy)alkyl]pyrroles are cleaved by base with the elimination of vinyl alcohol to give 1-vinylpyrroles.

Base-Mediated Addition of 1-(2-Hydroxyalkyl)pyrroles to Acetylene: Atom-Economic Route to 1-[2-(Vinyloxy)alkyl]pyrroles

Nucleophilic addition of 1-(2-hydroxyalkyl)pyrroles to acetylene, an unactivated carbon–carbon triple bond, in the presence of a base has been studied. As a result an atom-economic synthetic method to obtain 1-[2-(vinyloxy)alkyl]pyrroles in good yields employing superbase, sodium or potassium hydroxide in dimethyl sulfoxide, systems has been developed. 1-[2-(Vinyloxy)alkyl]pyrroles are cleaved by base with the elimination of vinyl alcohol to give 1-vinylpyrroles.

ChemInform Abstract: N‐Alkylations of NH‐Sulfoximines and NH‐Sulfondiimines with Alkyl Halides Mediated by Potassium Hydroxide in Dimethyl Sulfoxide.

A general method for the N-alkylation of NH-sulfoximines and NH-sulfondiimines has been developed, employing alkyl bromides with KOH in DMSO at room temperature. A variety of previously inaccessible N-alkylated sulfoximines and sulfondiimines was prepared in good to excellent yields (up to 97%). As an application, the conditions were used to access the biologically active Suloxifen.

N‐Alkylations of NH‐Sulfoximines and NH‐Sulfondiimines with Alkyl Halides Mediated by Potassium Hydroxide in Dimethyl Sulfoxide

AbstractA general method for the N‐alkylation of NH‐sulfoximines and NH‐sulfondiimines has been developed, employing alkyl bromides with KOH in DMSO at room temperature. A variety of previously inaccessible N‐alkylated sulfoximines and sulfondiimines was prepared in good to excellent yields (up to 97%). As an application, the conditions were used to access the biologically active Suloxifen.magnified image

Reactive Aramid Nanostructures as High‐Performance Polymeric Building Blocks for Advanced Composites

AbstractTraditionally, the field of advanced nanocomposites has relied on a fairly limited set of building blocks; many with low reactivity and of limited variability. These limitations have been addressed by the creation of functionalized nanometer‐scale aramid structures, in the form of nanofibers and nanosheets. These were obtained by deprotonating macroscale, commercial Kevlar yarns using potassium hydroxide in dimethyl sulfoxide to yield stable dispersions of nanometer‐scale aramid fibers that were then hydrolyzed using phosphoric acid (PA). To illustrate the use of these functionally‐active nanostructures as building blocks for nanocomposites, they were crosslinked by glutaraldehyde (GA), and formed into macroscopic thin films by vacuum‐assisted filtration. It was shown that the mechanical properties of these PA/GA treated films can be tuned by varying the amounts of PA and GA used during synthesis, adjusting the relative amounts of hydrolysis and polymerization. These results are the first demonstration that aramid nanometer‐scale fibers can be used to form versatile nanometer‐sized building blocks that can then be crosslinked to fabricate a wide variety of nanostructured aramid materials with tailorable properties.

Quantitative determination of superoxide in plant leaves using a modified NBT staining method

In plants, the ROS (reactive oxygen species) level is tightly regulated because their accumulation produces irreversible damage leading to cell death. However, ROS accumulation plays a key role in plant signaling under biotic or abiotic stress. Although various methods were reported to evaluate ROS accumulation, they are restricted to model plants or provide only qualitative information. Develop a simple method to quantify superoxide radicals produced in plant tissues, based on the selective extraction of the formazan produced after nitroblue tetrazolium (NBT) reduction in histochemical staining. Plant leaves were stained with a standard NBT method and the formazan precipitated in tissues was selectively extracted using chloroform. The organic phase was dried and formazan residue dissolved in dimethylsulfoxide-potassium hydroxide and quantified by spectrophotometry. The method was tested in strawberry plant leaves under different stressing conditions. Formazan extracted from leaves subjected to stress conditions showed similar absorption spectra to those obtained from standard solutions using pure formazan. Calibration curves showed a linear relationship between absorbance and formazan amounts, within the range 0.5-8 µg. Outcomes suggested that formazan was retained in the solid residue of leaf tissues. This protocol allowed us to quantify superoxide radicals produced under different stress conditions. Chloroform allowed a selective formazan extraction and removal of potential endogenous, exogenous or procedural artefacts that may interfere with the quantitative determination. This protocol can be used to quantify the superoxide produced in plant tissues using any traditional qualitative NBT histochemical staining method.

Flow Synthesis of Cyanine Dyes for Absorbing Orange Light from the Neon Gas Discharge

Color compensation technology made it possible to enhance the image quality of plasma panel display (PDP) devices. We examined the chemicals used in color compensation filters for PDP units in this study. Neon excitation during the plasma discharge causes orange light with an emission wavelength of 585 nm to be emitted from PDP devices. 1 This emitted orange light is mainly responsible for the degradation of color purity in PDP devices. 2 We synthesized three types of closed chain trimethine cyanines to attenuate unwanted spectral emissions having a wavelength 585 nm. Their common uses in PDP are near infrared absorbance filter. In this study, cyanines have been applied to neon orange light absorbing filter. By varying the number of carbons in the methine bridge of cyanine compound or by modifying the cyanine ring structure, 3,4 it is possible to synthesize cyanine structure absorbing particular wavelength and solvent solubility. A simple closed chain trimethine cyanine chromophore was synthesized by the condensation of 3-ethyl-2,4-dimethyl- pyrrole (kryptopyrrole) and TMOP with perchloric acid as shown in Scheme 1. Cyanine 1 was continuously synthesized using microchannel mixer and an extension tube. Kryptopyrrole was fed into one side of the microchannel mixer and the other reactants were fed into the other side. The reactants were mixed at the microchannel mixer and the reaction was carried out in the extension tube by heating at 60 o C. The microchannel mixer was operated at room temperature to avoid clogging it with precipitated solid particles. The volume of the extension tube was 10 mL, causing the retention time to vary from 0.37 s to 1.6 s depending on the total flow rate used in the experi- ment. We observed that a retention time of 0.37 s was sufficient to convert all reactants into product. A higher mass flow rate resulted in a shorter reactant retention time, thereby reducing the formation of byproducts. Cyanine 1 was produced with a yield of 95% and was 99.5% pure and dissolved in 2-butanone had a sharp absorption band at 580 nm with a half bandwidth of 36 nm. In comparison, azo or anthraquinone compounds typically had bandwidths of over 100 nm. 5 The width of the absorption band is dependent upon how closely the molecular structure in the first excited state resembles that in the ground state. The long conjugated chain structure of 1 was accompanied by a corresponding decrease in bandwidth. 6 The molar absorptivity of 1 was measured as 136,130 M -1 cm -1 . We synthesized a closed chain trimethine cyanine structure using 1-butyl-3-acetyl-2,4-dimethylpyrrole and 1,1,3,3-tetra- methoxypropane in the presence of perchloric acid as shown in Scheme 2. For the first step, several basic reagents were tested to generate a pyrrolyl anion for the alkylation of the nucleus in 3-acetyl-2,4-dimethylpyrrole with 1-bromobutane. Alkylation in the presence of potassium hydroxide in dimethyl sulfoxide gave 1-butyl-3-actyl-2,4-dimethylpyrrole with a 75 % yield. Other strong basic reagents such as potassium hydroxide in a solution of sodium amide or aqueous potassium hydroxide (50%) with tetrabutylammonium bromide in dichloromethane were also tested and delivered yields of 50% and 48%, respec- tively. Alkylation with sodium hydride in dimethyl sulfoxide increased the yield to 95%. The strong base, sodium hydride, reacts with dimethyl sulfoxide to produce dimsyl ions, which can effectively remove protons from the nucleus in 3-acetyl-2,4- dimethylpyrrole, thereby resulting in a more efficient alkylation with 1-bromobutane. The experimental result showed that 2 was obtained with a 70% yield and 98% purity. Some product loss took place during the washing and solid recovery steps. Cyanine 2 dissolved in 2-butanone had a maximum absorption at 580 nm with a half bandwidth of 39 nm. The molar absorp- tivity of 2 in 2-butanone was 32,303 M -1 cm -1 .

Synthesis and Characterization of Highly Soluble and Heat Stable New Poly(amide-ether)s Containing Pyridine Rings in the Main Chain

AbstractA pyridine-based diacid containing ether linkage was synthesized via reaction of 2,6-dichloropyridine with 3-hydroxybenzoic acid in presence of potassium hydroxide in dimethyl sulfoxide (DMSO). The corresponding diacid chloride was synthesized by reaction of the diacid with oxalyl chloride. New poly (amide-ether)s were prepared by solution polycondensation reaction of the prepared diacid chloride with different commercial aromatic diamines. The synthesized polymers were characterized by elemental analysis, IR, and 1H NMR spectra, wide-angle X-ray diffraction, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC); inherent viscosity and solubility were studied. These polymers showed high thermal stability and good solubility.

Products of the reaction of polychlorinated biphenyls with ethanol and potassium hydroxide in dimethyl sulfoxide

The reaction of a technical mixture of polychlorinated biphenyls with ethanol and potassium hydroxide in dimethyl sulfoxide was studied. The composition of the products formed in the process was determined by gas chromatography and gas chromatography mass spectrometry.

Spectrophotometric Study of Luminol in Dimethyl Sulfoxide–Potassium Hydroxide

The spectrophotometric study of luminol (LH2) in dimethyl sulfoxide (DMSO), DMSO-water solutions, and alkaline DMSO and DMSO-water solutions has been done, focusing on the effect of the KOH additon on LH2 absorption and fluorescence properties. The absorption spectra indicate an acid-base equilibrium, and the luminol dianion (L2−) formation at 3 × 10−4 − 2.4 × 10−3M KOH. The decrease of the fluorescence intensity and the variation of the excitation spectra of LH2-DMSO-KOH solutions with KOH concentration have been similarly explained. The acid-base process is reversible. The addition of HCl to the solution with 3.0 × 10−3 M KOH leads to an increase of the fluorescence intensity to its highest value, observed in pure DMSO. The addition of HCl to the LH2-DMSO solution leads to the decrease of the fluorescence intensity as a result of the LH+3 cation formation. In LH2-DMSO-water, the fluorescence band is shifted from 405 nm to 424 nm and increased in the intensity. In the presence of KOH (in LH2-DMSO-water-KOH solution) a new band appears, with the maximum at 485 nm and the band at 405 nm decreased. The changes in fluorescence lifetimes also evidence the different chemical species formed.

Conversions of Allyl Ethers in a Superbasic Medium

Conversions of alkyl allyl and terpenoid allyl ethers in a superbasic medium (dimethyl sulfoxidepotassium hydroxide) are studied. The ethers with an unbranched alkyl substituent isomerize into propenyl ethers, the ethers with a branched unsaturated substituent decompose to give a hydrocarbon, and diallyl ethers isomerize into allyl vinyl ethers whose Claisen rearrangement gives rise to aldehydes.

An expedient synthesis of isopropyl anisoles and veratroles

Isopropyl-substituted anisoles and veratroles were obtained in high yields (89–93 %) on the aqueous work-up of the reaction of 3-(methoxyphenyl)-2-oxopropanoic acids with iodomethane and potassium hydroxide in dimethyl sulfoxide.

A Facile Synthesis of Polyglycidyl Ethers from Polyols and Epichlorohydrin

The reaction of 1,1,1-tris(hydroxymethyl)ethane (1a), 2-ethyl-2-(hydroxymethyl)-1,3-propanediol (1b), pentaerythritol (1c), or 1,2, 6-hexanetriol (1e) with epichlorohydrin in the presence of potassium hydroxide in dimethyl sulfoxide gave the corresponding tri- or tetraglycidyl ethers 3a-c, e in high yields. This procedure was also applicable to the preparation of the phenolic polyglycidyl ethers

Reaction of 4-(N,N-Dimethylamino)-2-phenyl-2-(2-pyridyl)butanentrile and Related Compounds with Ethyl Chloroformate; Formation of Indolizinium and Quinolizinium Chlorides.

4-(N, N-Dialkylamino)-2-phenyl-2-(2-pyridyl)butanenitriles (10, 11 and 12) and 5-(N, N-dimethylamino)-2-phenyl-2-(2-pyridyl)pentanenitrile (13) react with ethyl chloroformate, via a cyclization-N-dealkylation process, to give indolizinium and quinolizinium salts (1 and 2). Compounds 1 and 2 are also obtained by reaction of the alcohol derivatives 14 and 15 with thionyl chloride. Reaction of 2-phenyl-2-(2-pyridyl)ethanenitrile (9) in the presence of potassium hydroxide in dimethyl sulfoxide, leading to [2-hydroxy-2-phenyl-2-(2-pyridyl)ethyl]methylsulfoxide (21), is also described.

Synthesis of pyrimidine derivatives using N‐bis(methylthio)methylenecyanamide

AbstractN‐Bis(methylthio)methylenecyanamide (1) was allowed to react with active methylene compounds (methyl cyanoacetate, dimethyl malonate, ethyl acetoacetate, ethyl phenylacetate) in the presence of potassium carbonate or potassium hydroxide in dimethyl sulfoxide followed by the treatment using appropriate a base or an acid to give the corresponding 6‐methylthiouracil derivatives in 15–80% yields.These uracil derivatives are found to be useful intermediates for the synthesis of 6‐aminouracils and fused pyrimidine derivatives.

Synthesis and antibacterial activity of some 1-(2-propynyl) and 1-propadienyl derivatives of 1,4-dihydro-4-oxoquinoline-3-carboxylic acids and similar heterocycles

N-Alkylation of IIIa, IIIb, IIId - IIIf and 9-acridanone with 3-bromopropyne in dimethyl sulfoxide in the presence of potassium carbonate yielded N-(2-propynyl) derivatives IVa - IVe and VIa, respectively. Ethyl esters IVa, IVb, and IVe were hydrolyzed to IVf - IVh, respectively. Compounds IVf, IVg, IVctreated with bases yielded N-propadienyl derivatives Va - Vc. On the other hand 2-substituted compounds IVd and IVh did not change under the same conditions. Compound VIa treated with powdered potassium hydroxide in dimethyl sulfoxide at room temperature yielded N-(1-propynyl) derivative VII.

ChemInform Abstract: Methylation of Bidentate Nitrogen‐Containing Heterocycles with Methyl Iodide and Potassium Hydroxide in Dimethyl Sulfoxide.

ChemInformVolume 21, Issue 22 Heterocyclic Compounds ChemInform Abstract: Methylation of Bidentate Nitrogen-Containing Heterocycles with Methyl Iodide and Potassium Hydroxide in Dimethyl Sulfoxide. E. GIORGINI, E. GIORGINI Dip. Sci. Mat. Terra, Univ. Stud., 60131 Ancona, ItalySearch for more papers by this authorL. GRECI, L. GRECI Dip. Sci. Mat. Terra, Univ. Stud., 60131 Ancona, ItalySearch for more papers by this authorG. TOSI, G. TOSI Dip. Sci. Mat. Terra, Univ. Stud., 60131 Ancona, ItalySearch for more papers by this authorV. BOCCHI, V. BOCCHI Dip. Sci. Mat. Terra, Univ. Stud., 60131 Ancona, ItalySearch for more papers by this author E. GIORGINI, E. GIORGINI Dip. Sci. Mat. Terra, Univ. Stud., 60131 Ancona, ItalySearch for more papers by this authorL. GRECI, L. GRECI Dip. Sci. Mat. Terra, Univ. Stud., 60131 Ancona, ItalySearch for more papers by this authorG. TOSI, G. TOSI Dip. Sci. Mat. Terra, Univ. Stud., 60131 Ancona, ItalySearch for more papers by this authorV. BOCCHI, V. BOCCHI Dip. Sci. Mat. Terra, Univ. Stud., 60131 Ancona, ItalySearch for more papers by this author First published: May 29, 1990 https://doi.org/10.1002/chin.199022145Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume21, Issue22May 29, 1990 RelatedInformation

ChemInform Abstract: Reaction of Cholesterol with Benzophenone in the Presence of Potassium Hydroxide in Dimethyl Sulfoxide.

ChemInform Abstract: Reaction of Cholesterol with Benzophenone in the Presence of Potassium Hydroxide in Dimethyl Sulfoxide.

Synthesis and reaction of 6‐substituted 3‐methoxycarbonyl‐4‐methylthio‐2H‐pyran‐2‐one derivatives

AbstractReaction of aryl and styryl methyl ketones 1a‐m with dimethyl bis(methylthio)methylenemalonate (2) in the presence of potassium hydroxide in dimethyl sulfoxide gave the corresponding methyl 6‐aryl‐ and 6‐styryl‐4‐methylthio‐2‐oxo‐2H‐pyran‐3‐carboxylates 3a‐m.6‐Aryl derivatives 3a‐d,g were treated with sodium methoxide in methanol to give the corresponding 6‐aryl‐4‐methoxy‐2H‐pyran‐2‐ones 8a‐d and 9. Phenylcoumalin (7a) and paracotoin (7b) were synthesized by the desulfurization of 6‐aryl‐4‐methylthio‐2H‐pyran‐2‐ones 4a,b. Similarly, anibine (8e) was also synthesized from 3g.Treatment of 3 with hydrogen peroxide or 3‐chloroperoxybenzoic acid gave the corresponding 4‐methylsulfiny‐2H‐pyran‐2‐ones 10a‐f in good yields. Displacement reactions of 10a‐f with nucleophilic reagents are also described.